Use fixed version of ubuntu (#48)

We want to pin all our dependencies, so that our builds are
reproducible.

.github/workflows/check-commit-message.yml

@@ -15,7 +15,7 @@ jobs:
   check-commit-message-style:
     if: (github.actor!= 'dependabot[bot]') && (contains(github.head_ref, 'dependabot/github_actions/') == false)
     name: Check commit message style
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Check
         uses: mristin/[email protected]

.github/workflows/check_semver_labels.yml

@@ -13,7 +13,7 @@ jobs:
 
   check_semver_label:
     name: Check for semantic version label
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: docker://agilepathway/pull-request-label-checker:v1.0.9
         with:

.github/workflows/dependabot_hack.yml

@@ -9,7 +9,7 @@ jobs:
 
   dependabot_hack:
     name: Ensure dependabot version checks
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
 
       # update the version manually in these places, too:

.github/workflows/github_tag_and_release.yml

@@ -10,7 +10,7 @@ jobs:
 
   tag:
     name: Tag semantic version
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Tag
         uses: K-Phoen/[email protected]
@@ -23,7 +23,7 @@ jobs:
   release:
     needs: tag
     name: Create GitHub Release
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       -
         name: Checkout

.github/workflows/reviewdog.yml

@@ -7,7 +7,7 @@ jobs:
 
   hadolint:
     name: runner / hadolint
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Check out code
         uses: actions/[email protected]
@@ -19,7 +19,7 @@ jobs:
 
   yamllint:
     name: runner / yamllint
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: yamllint
@@ -30,7 +30,7 @@ jobs:
 
   shellcheck:
     name: runner / shellcheck
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: shellcheck
@@ -44,7 +44,7 @@ jobs:
 
   misspell:
     name: runner / misspell
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - uses: reviewdog/[email protected]
@@ -54,7 +54,7 @@ jobs:
 
   languagetool:
     name: runner / languagetool
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - uses: reviewdog/[email protected]

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
 
   install_latest_version_by_default:
     name: Install latest version by default
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: Install Hoverfly
@@ -30,7 +30,7 @@ jobs:
 
   install_specific_version:
     name: Install specific version
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       HOVERFLY_VERSION: v1.2.0
     steps:
@@ -48,7 +48,7 @@ jobs:
 
   install_fails_if_version_does_not_begin_with_v:
     name: Install fails if version does not begin with v
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       HOVERFLY_VERSION: "1.2.0"
     steps:
@@ -66,7 +66,7 @@ jobs:
 
   install_fails_if_no_runner_github_workspace_path:
     name: Install fails when no runner GitHub workspace path provided
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: Install Hoverfly
@@ -79,7 +79,7 @@ jobs:
 
   install_fails_if_incorrect_runner_github_workspace_path:
     name: Install fails when incorrect runner GitHub workspace path provided
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: Install Hoverfly
@@ -94,7 +94,7 @@ jobs:
 
   use_script_to_enable_https_simulations:
     name: Enable https simulations
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: Install Hoverfly
@@ -115,7 +115,7 @@ jobs:
 
   https_simulations_do_not_work_without_https_script:
     name: Verify https simulations will not work without script
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/[email protected]
       - name: Install Hoverfly